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Abstract & Commentary
Synopsis: Multivessel PCI in acute MI may be associated with increased risk of adverse outcomes.
Source: Roe MT, et al. Am J Cardiol. 2001;88:170-173.
Multivessel percutaneous coronary inter-vention (PCI) in the setting of mechanical reperfusion as primary or rescue therapy for acute myocardial infarction (MI) has not been widely studied. The goal of this retrospective analysis was to compare the feasibility and safety of PCI of diseased nonculprit vessels in the acute MI setting. Roe and colleagues compare outcomes in 79 patients who underwent nonculprit, in addition to infarct-related artery (IRA) PCI. Control cases were matched on the basis of age and Killip classification at presentation. Angiograms were evaluated at a central core laboratory. The primary end point was the composite of death, reinfarction, repeat PCI, or need for coronary artery bypass graft (CABG) surgery at 6 months of follow-up. Other clinical end points evaluated included stroke and bleeding complications requiring transfusion.
Baseline characteristics were comparable between the multivessel PCI group and the control IRA-only PCI group. The percentages of patients undergoing primary PCI vs. rescue PCI (for unsuccessful thrombolytic therapy) were comparable between the 2 groups. The time from symptom onset to balloon inflation was somewhat lower in the multivessel PCI group, with 60% of these patients receiving treatment within 6 hours compared with 44% in the IRA-only group. The groups were well matched in terms of IRA location. Success rates for IRA PCI were equivalent between the 2 groups (98.7%) and nonculprit PCI was successful in 97% of patient in whom it was attempted. There were no differences in the rates of intra-aortic balloon pump supporter platelet glycoprotein IIb-IIIa inhibitor use between the 2 groups. Patients in the multivessel PCI group were more likely to receive stenting of the IRA (70% vs 45%), but there was no significant difference in the frequency with which TIMI 3 flow was established.
There was no difference between the multivessel and the IRA-only control patients in the frequency of the composite end point at 6 months. There was a non-significant trend toward increased mortality at 30 days and 6 months in the patients who underwent multivessel PCI for both primary (22.1% vs 11.5%) and rescue indications (18.2% vs 16.7%). There was an increased risk of stroke in the patients who received multivessel PCI (10.3% vs 0%; P = 0.01). There were no significant differences between the groups in rates of other individual clinical end points, but there was a trend toward higher rates of reinfarction in patients receiving multivessel PCI as primary therapy (8.8% vs 1.6%; P = 0.07).
The results suggest that multivessel PCI in acute MI may be associated with increased risk of adverse outcomes. However, Roe et al state that potential benefits of multivessel PCI in acute MI might not have been uncovered in this study. Of particular interest would be those potential benefits in patients with reduced left ventricular function or cardiogenic shock at presentation. Roe et al acknowledge that this analysis has multiple limitations, most notably small sample size, retrospective design, and possibility of selection bias in patients selected to receive multivessel revascularization at the time of acute MI. They further outline the need for prospective randomized trials to better define the optimal revascularization strategy for patients with multivessel disease who undergo PCI for acute MI.
Comment by Sarah M. Vernon, MD
Accumulating evidence suggests that primary PCI is the superior strategy for the revascularization of patients with acute MI when it is performed in centers and by operators with adequate experience in this technique. Not infrequently, when undergoing diagnostic coronary angiography at the time of acute MI, these patients are found to have multivessel disease in addition to involvement of the IRA. While it is true that outcomes of multivessel PCI with contemporary techniques (most notably the widespread use of coronary stenting) have improved markedly and are now comparable to surgical revascularization in many subgroups of patients, these data probably are not applicable to patients with acute MI. In fact, the recently revised ACC/AHA guidelines assign elective PCI of a noninfarct-related artery at the time of acute MI a Class III designation (condition for which there is evidence and/or general agreement that the procedure/treatment is not useful/effective, and in some cases may be harmful), with a supporting level of evidence C (consensus of expert opinion). Despite this recommendation, many interventionalists have had the experience of being tempted (or pressured) into intervening on lesions in the non-IRA vessels in the same sitting as a successful primary PCI. This can occur for a variety of reasons, ranging from patient or referring physician preference, expediency, economic or length-of-stay concerns, or simply the presence of a particularly "juicy" type-A lesion in a noninfarct-related artery. While multivessel PCI may ultimately prove to be an acceptable or even optimal strategy for revascularization in this setting, this report from Roe and colleagues further supports the "look but don’t touch" approach to disease in the noninfarct-related vessels in patients with acute MI.
1. Smith SC, et al. J Am Coll Cardiol. 2001;37(8): 2215-2238.